Browsing by Author "Kasimanickam, Ramanathan K."

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    Antibacterial efficacy of core-shell nanostructures encapsulating gentamicin against an in vivo intracellular Salmonella model
    Ranjan, Ashish; Pothayee, Nikorn; Seleem, Mohamed N.; Tyler, Ronald D.; Brenseke, Bonnie; Sriranganathan, Nammalwar; Riffle, Judy S.; Kasimanickam, Ramanathan K. (Dove Medical Press, 2009-01-01)
    Pluronic based core-shell nanostructures encapsulating gentamicin were designed in this study. Block copolymers of (PAA(+/-)Na-b-(PEO-b-PPO-b-PEO)-b-PAA(+/-)Na) were blended with PAA(-) Na(+) and complexed with the polycationic antibiotic gentamicin to form nanostructures. Synthesized nanostructures had a hydrodynamic diameter of 210 nm, zeta potentials of -0.7 (+/-0.2), and incorporated approximately 20% by weight of gentamicin. Nanostructures upon co-incubation with J774A.1 macrophage cells showed no adverse toxicity in vitro. Nanostructures administered in vivo either at multiple dosage of 5 microg g(-1) or single dosage of 15 microg g(-1) in AJ-646 mice infected with Salmonella resulted in significant reduction of viable bacteria in the liver and spleen. Histopathological evaluation for concentration-dependent toxicity at a dosage of 15 microg g(-1) revealed mineralized deposits in 50% kidney tissues of free gentamicin-treated mice which in contrast was absent in nanostructure-treated mice. Thus, encapsulation of gentamicin in nanostructures may reduce toxicity and improve in vivo bacterial clearance.
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    Calm Temperament Improves Reproductive Performances of Beef Cows
    Whittier, William Dee; Kasimanickam, Ramanathan K.; Assay, M.; Schroeder, S.; Kasimanickam, Vanmathy R.; Gay, John M.; Hall, John B. (Virginia Tech. Powell River Project, 2015)
    Profitability of a beef operation is determined by breeding season pregnancy rates and proportion of cows attaining pregnancy early in the breeding season. Many factors including temperament contribute to these reproductive parameters. The objective of this study was to evaluate the effect of temperament on reproductive performances of beef cows. In experiment 1, Angus and Angus cross beef cows (n=1546) from 8 locations received body condition score (BCS; 1-emaciated; 9-obese) and chute-exit and gait score (1 = slow exit, walk; calm temperament; 2 = jump, trot or run; excitable temperament). Cows were grouped with bulls (1:25 to 1:30; with satisfactory breeding potential and free of venereal disease) during the entire 85 day breeding season. Pregnancy status and gestation length of cows was determined by per-rectal palpation at 35 days after the end of the breeding season. Controlling for BCS (P<0.01) and handling facility (P<0.0001) and handling facility by temperament score interaction (P<0.001) the breeding season pregnancy rate was different between excited and calm cows [88.6% (798/901) vs. 94.1% (607/645); P<0.001]. Cows with excitable temperament took 24 more days to become pregnant in the 85 day breeding season compared to calm cows (median days to pregnancy: 35 vs. 59 days; P<0.0001). In experiment 2, Angus and Angus cross beef cows (n=1407) from 8 locations received body condition score (BCS; 1-emaciated; 9-obese) and chute-exit and gait score (1 = slow exit, walk; calm temperament; 2 = jump, trot or run; excitable temperament). All cows were grouped with bulls (1:25 to 1:30; with satisfactory breeding potential and free of venereal disease) during the entire 85 day breeding season. Pregnancy status was determined by per-rectal palpation at 2 and 6 months from the beginning of the breeding season to determine the pregnancy loss. Controlling for BCS (P<0.05), the pregnancy loss was different between excited and calm cows, 5.5 (36/651) vs 3.2 (20/623), respectively (P<0.05) In conclusion, beef cows with excitable temperament had lower reproductive performance than calmer cows. The modified 2-point chute exit-gait scoring method is repeatable and can be used to identify cattle with excitable temperament.
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    Fertility in Angus Cross Beef Cows Following 5d CO-Synch + CIDR or 7d CO-Synch + CIDR Estrus Synchronization and Timed Artificial Insemination
    Whittier, William Dee; Currin, John F.; Schramm, Holly; Holland, Sarah; Kasimanickam, Ramanathan K. (Virginia Tech. Powell River Project, 2013)
    The present study determined whether a 5d CO-Synch + CIDR protocol with a two doses of prostaglandin F2α (PGF) would improve timed AI pregnancy rate compared to 7d CO-Synch + CIDR protocol in beef cows. Angus cross beef cows (N = 1817) at 12 locations were randomly assigned to 5d CO-Synch + CIDR or 7d CO-Synch + CIDR groups. All cows received 100 μg of gonadorelin diacetate tetrahydrate (GnRH) and a controlled internal drug release (CIDR) insert on Day 0. Cows (n=911) in the 5d CO-Synch + CIDR group received two doses of 25 mg PGF, the first dose given on Day 5 at CIDR removal and the second dose 6 h later, and 100 μg GnRH on Day 8 and were inseminated concurrently, 72 h after CIDR removal. Cows (n=906) in 7d CO-Synch + CIDR group, received 25 mg of PGF at CIDR removal on Day 7, and 100 μg GnRH on Day 10 and were inseminated concurrently, 66 to 72 h after CIDR removal. All cows were fitted with a heat detector aid at CIDR removal and were observed twice daily until insemination for estrus and heat detector aid status. Accounting for estrus expression at or prior to AI (P<0.0001) and body condition score (P<0.01), cows in the 5d CO-Synch + CIDR group had greater AI pregnancy rate compared to cows in the 7d CO-Synch + CIDR groups (58.1% vs. 55.1%; P = 0.04). More cows that exhibited estrus at or prior to AI became pregnant compared to cows that did not [65.7% (681/1037) vs. 44.5% (347/780); P<0.0001]. The AI pregnancy rate was lesser for cows with body condition ≤ 4 (≤ 4 – 49.3% (101/219), 5 to 6 – 57.9%; > 6 – 55.8%). The mean AI pregnancy rate difference between treatment groups and projected economic outcome varied among locations. In conclusion, cows synchronized with the 5d COSynch + CIDR protocol had greater AI pregnancy rate than those that received the 7d CO-Synch + CIDR protocol.
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    Impact of Body Condition Change Post-Breeding on Reproductive Performance of Beef Cows
    Kasimanickam, Ramanathan K.; Firth, Phillip; Asay, Matthew; Tibary, Ahmed; Moore, Dale; Hall, John; Whittier, William Dee (Virginia Tech. Powell River Project, 2014)
    Body condition score (BCS) is a commonly used tool for evaluating the nutritional status of beef cows. Good nutritional status of beef cows is one of the essential components for improved reproductive performance. The objective was to evaluate the impact of change in body condition during 2 months after breeding on the AI pregnancy success in beef cows. Angus cross beef cows (N = 2571) from 11 locations were included in this study. All cows were given a BCS (1-emaciated; 9-obese), by the same clinician in each location at the initiation of the synchronization (CO-Synch+CIDR) protocol and again at pregnancy diagnosis, 60 to 70 days later. Cows were fitted with Kamar heat detection patches at CIDR removal and observed three times daily for estrus expression until timed insemination. Cow’s Cows’ pregnancy status was determined by per-rectal palpation or using ultrasonography. Variables included in the model (PROC MIXED) were change in BCS (no change or gain vs. loss), cows expression of estrus at or prior to AI (activated, partially activated, or lost Kamar) or not (intact Kamar), age of the dam (2, 3 to 6 and >6 years), days post calving at initiation of synchronization (30 to 60, 61 to 80 and > 81 days) and appropriate 2-way interactions. Season (location) and AI sires were considered as random effects. The results showed AI pregnancy rate was influenced by change in the BCS [No change or gain: 55.3%; (1034/1870) vs loss: 50.1% (352/703); P<0.05] and cows that showed estrus at or prior to AI [estrus: 57.8% (825/1423) vs no estrus: 48.9% (560/1148); P<0.0001]. In conclusion, cows that lost body condition between breeding and pregnancy diagnosis had lower AI pregnancy rates compared to cows that maintained or gained body condition. It is essential to feed cows following breeding to maintain their BCS in order to optimize their conception rates.
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    Tocopherol induced angiogenesis in placental vascular network in late pregnant ewes
    Kasimanickam, Ramanathan K.; Kasimanickam, Vanmathy R.; Rodriguez, Jacobo S.; Pelzer, Kevin D.; Sponenberg, D. Phillip; Thatcher, Craig D. (2010-07-12)
    Background Tocopherols have biphasic, proangiogenic and antiangiogenic therapeutic effects. The objective of this clinical trial was to clarify tocopherol's placental angiogenic potential in late pregnant ewes following oral supplementation. Methods Eighteen pregnant ewes during late gestation were selected for this study. Ewes were given oral supplementation of 500 mg of alpha-tocopherol (aT; N = 6) or 1000 mg of gamma-tocopherol (gT; N = 7) or placebo (CON; N = 5) once daily from 107 to 137 days post breeding. Serum was obtained at weekly intervals and tissue samples were obtained at the end of supplementation to: 1) evaluate tocopherol concentrations in serum, uterus and placentome; 2) evaluate relative mRNA expressions of Vascular Endothelial Growth Factor (VEGF), Placental Growth Factor (PlGF), endothelial Nitric Oxide Synthase (eNOS) and Hypoxia Inducible Factors (HIF) in uterus, caruncle and cotyledon; 3) analyze the morphometry of the placental vascular network. Results Supplementation of aT or gT resulted in increased concentrations in serum, placentome and uterus compared to control (P < 0.05). In aT group, mRNA expressions of PlGF, eNOS and HIF-1α in cotyledon were greater than the CON group. In gT group, mRNA expressions of VEGF, eNOS, HIF-1 alpha and HIF-2 alpha in caruncle and uterus, and HIF-1α in cotyledon, were greater than the CON group. Morphometry analysis revealed increased angiogenesis in the supplemented groups. Conclusion Daily oral supplementation of aT or gT increased angiogenesis in the placental vascular network in pregnant ewes during late gestation. Increase in placental angiogenesis may provide nutrients required for the development and growth of fetus during late pregnancy.